Sorption of NbF5 from UF6-containing gases on granulated sodium and magnesium fluorides

The capacity for NbF₅ of granulated sodium fluoride at 100 and 400°C and of magnesium fluoride at 125°C was determined. The choice of the sorbents and temperatures is governed by the possibility of using the sorbents at these temperatures for decontamination of UF₆ from fission product impurities in reprocessing of spent nuclear fuel by the fluoride volatility technology. The presence of UF₆ in the gases does not appreciably affect the sorbent capacities. Sodium fluoride at 400°C is suitable for decontamination of UF₆ from NbF₅ as one of impurities.     

Antisite Defects in Ge–Te and Ge–As–Te Semiconductor Glasses

Semiconductors - The formation of antisite defects in Ge20Te80 and Ge15As4Te81 vitreous alloys in the form of tin atoms in tellurium sites and tellurium atoms in germanium sites is shown by...     

Variation in the State of 119mSn Impurity Atoms in PbTe during the Establishment of the Radioactive Equilibrium of 119mTe/119Sb Isotopes

Semiconductors - The parameters of the emission Mössbauer spectra of PbTe using the 119mSn daughter isotope with different parent nuclei 119mmSn, 119Sb, and 119mTe are compared. This...     

"Microduplex" structure in industrial aging alloys

Conclusion Finely disperse biphase structure (microduplex) forms in the process of high-temperature recrystallization of strongly deformed alloys containing particles of -phase in the deformed lattice.Novosibirsk Institute of Railroad Transport Engineers. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, p. 40, June, 1984.     

The influence of amorphization on the local environment of atoms in arsenic chalcogenides

The influence of amorphization on the symmetry of the local environment of chalcogen atoms in the As₂S₃, As₂Se₃, and As₂Te₃ compounds is investigated using Mössbauer emission spectroscopy. In the ¹²⁹Te(¹²⁹I) Mössbauer emission spectra of crystalline As₂Te₃, three states of threefold-coordinated tellurium atoms appear to be indistinguishable. The transformation of the As₂Te₃ crystalline compound into the vitreous state results in the lowering of the local symmetry of threefold-coordinated states of the tellurium atoms and the formation of twofold-coordinated states of the tellurium atoms in chains of the type-As-Te-Te-As-. Two states of twofold-coordinated chalcogen (X) atoms in chains of the type-As-X-As-in the structure of the As₂S₃ and As₂Se₃ crystalline compounds manifest themselves in the form of a broadening of the Mössbauer spectra. The transformation of the As₂S₃ and As₂Se₃ crystalline compounds into the vitreous state is not accompanied by a change in the local symmetry of twofold-coordinated chalcogen atoms in chains of the type-As-X-As-; however, the structure of the glass in this case is characterized by the formation of twofold-coordinated states of sulfur and selenium atoms in chains of the type-As-X-X-As-. The fraction of twofold-coordinated chalcogen atoms increases upon changing over from As₂ X ₃to AsX.     

Electrical properties and structure of chalcogenide glasses containing bivalent tin

Two valence states of tin atoms are identified by Mössbauer and X-ray photoelectron spectroscopy in (As₂Se₃)_1?z (GeSe) _z?x (SnSe) _x glasses; it is shown that the presence of bivalent tin in the structural network of a glass does not give rise to impurity conductivity and impurity optical absorption. It is suggested to regard (As₂Se₃)_1?z (GeSe) _z?x (SnSe) _x and (As₂Se₃)_1?z (GeSe₂) _z?x (SnSe₂) _x glasses as semiconductor solid solutions whose electrical properties depend both on the electrical properties of the starting components and on the composition of the solid solutions.     

Possibility of observing Bose-Einstein condensation in semiconductors via Mössbauer spectroscopy using the 67Zn isotope

It has been determined using emission Mössbauer spectroscopy on ⁶⁷Cu(⁶⁷Zn) and ⁶⁷Ga(⁶⁷Zn) isotopes that a transition to the superconducting state leads to a change of the electron density on the metal sites of the crystal lattices of the copper-metal oxides Nd_1.85Ce_0.15CuO₄, La_0.18Sr_0.15CuO₄, YBa₂Cu₃O_6.6, YBa₂Cu₃O_6.9, YBa₂Cu₄O₈, Bi₂Sr₂CaCu₂O₈, Tl₂Ba₂CaCu₂O₈, HgBa₂CuO₄, and HgBa₂CaCu₂O₄. A correlation between the change in electron density and the temperature of the crystal transition to the superconducting state is found. The expected change of the electron density on ⁶⁷Zn nuclei for materials with a phase transition temperature below 10 K turns out to be negligible. That is why the reliable observation of a change of the electron density for the superconducting transition in semiconductors with the use of spectroscopy on the ⁶⁷Zn isotope appears to be unlikely.